A Measured Approach Key to Treating Mycosis Fungoides

HUNTINGTON BEACH, California — When patients of Aaron Mangold, MD, first learn they have mycosis fungoides (MF), the most common form of primary cutaneous T-cell lymphoma (CTCL), some are concerned about whether the diagnosis means a shortened life expectancy.

“In most cases, mycosis fungoides will not shorten one’s life, but it can cause significant symptoms,” Mangold, co-director of the multidisciplinary cutaneous lymphoma clinic at Mayo Clinic, Scottsdale, Arizone, said at the annual meeting of the Pacific Dermatologic Association. “For early-stage disease, I think of it more like diabetes; this is really a chronic disease” that unlikely will be fatal but may be associated with increased morbidity as the disease progresses, and “the overall goal of therapy should be disease control to increase quality of life,” he said.

Patient- and lymphoma-specific factors drive the choice of therapy. The focus for early-stage disease patients, Mangold said, is to treat comorbidities and symptoms, such as itch or skin pain, maximize their quality of life, and consider the potential for associated toxicities of therapy as the disease progresses. Start with the least toxic, targeted, non-immunosuppressive therapy, “then work toward more toxic immunosuppressive therapies,” he advised. “Use toxic agents just long enough to control the disease, then transition to a maintenance regimen with less toxic immunosuppressive agents.”

When Close Follow-Up is Advised

According to unpublished data from PROCLIPI (the PROspective Cutaneous Lymphoma International Prognostic Index) study presented at the 5th World Congress of Cutaneous Lymphomas earlier this year, the following factors warrant consideration for close follow-up and more aggressive treatment: Nodal enlargement greater than 15 mm, age over 60 years, presence of plaques, and large-cell transformation in skin. “These are some of the stigmata in early disease that might guide you toward referring” a patient to a CTCL expert, he said. (Consensus-based recommendations on the management of MF in children were published in August of 2024.)

According to Mangold, topical/skin directed therapies are best for early-stage disease or in combination with systemic therapies in advanced disease. For early-stage disease, one of his preferred options is daily application of a skin moisturizer plus a topical corticosteroid such as clobetasol, halobetasol, or augmented betamethasone, then evaluating the response at 3 months. “This is a cheap option, and we see response rates as high as 90%,” he said. “I don’t often see steroid atrophy when treating patients with active MF. There’s a tendency to think, ‘I don’t want to over-treat.’ I think you can be aggressive. If you look in the literature, people typically pulse twice daily for a couple of weeks with a 1-week break.”

Mechlorethamine, a topical alkylating gel approved in 2013 for the treatment of early-stage MF, is an option when patients fail to respond to topical steroids, prefer to avoid steroids, or have thick, plaque-like disease. With mechlorethamine, it is important to “start slow and be patient,” Mangold said. “Real-world data shows that it takes 12-18 months to get a good response. Counsel patients that they are likely to get a rash, and that the risk of rash is dose dependent.”

Other treatment options to consider include imiquimod, which can be used for single refractory spots. He typically recommends application 5 days per week with titration up to daily if tolerated for up to 3 months. “Treat until you get a brisk immune response,” he said. “We’ve seen patients with durable, long-term responses.”

UVB Phototherapy Effective

For patients with stage IB disease, topical therapies are less practical and may be focused on refractory areas of disease. Narrow-band UVB phototherapy is the most practical and cost-effective treatment, Mangold said. Earlier stage, patch disease responds to phototherapy in up to 80% of cases, he said, while plaque stage disease responds in up to half of cases. “More frequent use of phototherapy may decrease time to clearance, but overall response is similar,” he noted.

Mangold recommends phototherapy 2-3 days per week, titrating up to a maximal response dose, and maintaining that dose for about 3 months. Maintenance involves tapering the phototherapy dose to a minimal dose with continued response. “The goal is to prevent relapse,” he said.

For patients with MF that is stage IIB and higher, he considers total skin electron beam therapy, an oral retinoid with phototherapy, systemic agents, and focal radiation with systemic treatment. One of his go-to systemic options is bexarotene, which he uses for early-stage disease refractory to treatment or for less aggressive advanced disease. “We typically use a low dose…and about half of patients respond,” Mangold said. The time to response is about 6 months. Bexarotene causes elevated lipids and low thyroid function, so he initiates patients on fenofibrate and levothyroxine at baseline.

Another systemic option is brentuximab vedotin, a monoclonal antibody that targets cells with CD30 expression, which is typically administered in a specialty center every 3 weeks for up to 16 cycles. “In practice, we often use 6-8 cycles to avoid neuropathy,” he said. “It’s a good debulking agent, the time to response is 6-9 weeks, and it has a sustained response of 60%.” Neuropathy can occur with treatment, but improves over time, he said.

Other systemic options for MF include romidepsin, mogamulizumab, and extracorporeal photopheresis, used in erythrodermic disease.

Radiation An Option in Some Cases

Mangold noted that low doses of radiation therapy can effectively treat MF lesions in as little as one dose. “We can use it as a cure for a single spot or to temporarily treat the disease while other therapies are being started,” he said. Long-term side effects need to be considered when using radiation, he cautioned. “The more radiation, the more side effects.”

Mangold disclosed that he is an investigator for Sun Pharmaceutical, Solagenix, Elorac, miRagen, Kyowa Kirin, the National Clinical Trials Network, and CRISPR Therapeutics. He has also received consulting fees/honoraria from Kirin and Solagenix.